Vacuum lifting-cup.



C. L. SMITH.

VACUUM LIFTING CUP.

APPLICATION FILED APR. 23. 1915.

Patented May 8, 1917.

IINI IED TATE FAIENT @FFIQE.

GARIJTQN 1:. SMITH, OF SAGINAW, MICHIGAN, ASSIGNOR T0 SAGINAW PLATE GLASS COMPANY, SAGINAW, MICHIGAN, A CORPORATION OF MICHIGAN.

VACUUM LIFTING-CUP.

Specification of Letters Patent.

Patented May 8, 1917.

Application filed April 23, 1915. Serial No. 23,412.

To all whom it may concern:

Be it known that I, CARLTON L. SMITH, a citizen of the United States, and a rcsident of Saginaw, in the county of Saginaw and State of Michigan, have invented a certain new and useful Improvement in Vacuum Lifting-Cups, of which the following is a specification.

This invention relates to vacuum lifting machines, and relates particularly to an improved diaphragm for the vacuum cups of vacuum lifting machines for handling plate glass and like products, of the general type shown and described in U. S. Letters Patent No. 1,125,752, issued to me J anuary 19, 1915.

The lifting or load carrying capacity of vacuum cups of the kind referred to, cannot exceed 15 lbs. per sq. inch, that is the suction of a perfect vacuum and will decrease as the percentage of vacuum decreases.

In the form of suction diaphragm shown in said Letters Patent No. 1,125,752 the surface of said diaphragm, which contacts with the glass, is perfectly flat and, though made of rubber or other soft, pliable and elastic mamrial, willnot conform to irregularities in the surface of the material to be handled, as rough plate glass.

When a suction diaphragm which is flat throughout is applied to an uneven plain surface and the air exhausted from the vacuum cup, the action of the vacuum will progress outwardly from points of communication with said vacuum cup. lVhile, in this manner, a strong engagement will be secured between the suction diaphragm and the surface of the article to be handled, adjacent to such points of communication with the vacuumcup, and which may even be strong enough to cause said diaphragm to conform to irregularities in the surface of the article, such contact will operate, in an obvious manner, to partially and perhaps wholly cut off the outer edges of said diaphragm from the action of the Vacuum cup. Where the surface of the article is irregular, therefore, points of non-contact between said diaphragm and article will occur at depressions in the surface of the article in the portions of said diaphragm which are those out off from said vacuum, and these points of non-contact will form pockets which will contain air under practically atmospheric pressure. Such pockets will therefore reduce the lifting orload carrying power of the vacuum cup in the proportion which the aggregate area of said pockets bears to the entire area of the diaphragm, which, in practice, is found to be sufficiently large to materially reduce the estimated lifting or load carrying power of said vacuum cup.

I have discovered that a much more perfect contact may be secured between the diaphragm and an irregular surface to which it is applied, as the rough surface of unpolished plate glass, by cupping the suction diaphragm adjacent to its outer edge, whereby, when said suction diaphragm is applied to the surface of the glass and the air is eX- haustedfrom the vacuum cup, the exhaustion of the air from between said diaphragm and the surface of the glass will proceed progressively from the outer edge of the diaphragm toward its center, instead, as here tofore, of progressing from the center outwardly. In this manner, the air is exhausted from between said suction diaphragm and the surface of the glass much more perfectly than with a perfectly flat diaphragm, producing a much more perfect and thorough contact of said suction diaphragm with the surface of the glass and correspondingly increasing the lifting or carrying power of the vacuum cup.

The object of my present invention is, therefore, to increase the lifting or load carrying power of vacuum cups of the general type to which my invention relates. And to this end my invention comprises the various features, combinations of features and details of construction hereinafter described and claimed.

In the accompanying drawing, in which my invention is fully illustrated- Figure l is a central sectional view of a vacuum cup equipped with a suction diaphragm of my invention, as it will appear when not in use.

Fig. 2 is a similar view showing the same as applied in use; and

Figs. 3 and a are top and bottom plan views, of the suction diaphragm when not in use, as shown in Fig. 1.

In the drawing, I have, for purposes of concrete illustration, shown my improved suction diaphragm as applied in use to a vacuum cup similar to those shown and described in said U. S. Letters Patent No.

rest upon and to be riveted or otherwise rigidly secured to frame members, not shown;

As shown, said projections or brackets 23 are reinforced or strengthened by means of ribs or flanges 1.

Formed at the lower end of the casing 1 a flange 5 and secured in the open end of said casing is a spider 6, said spider being provided with a central opening 7' and with a plurality of openings 8 urrounding said central opening 7.

The spider 6 is secured in the end of the casing 1 with a driving fit, the position of said spider being defined by abutting shoulders 9 formed on said casing and on said spider and the lower 'ides of said flange 5 and spider 6 being dressed to form a substantiallytrue and continuous surface.

Secured to the under face of the casing 1 is a dia1i hragm 10 of suitable flexible material impermeable to air,-preferably rubber or the like. As shown, the diaphragm 10 is clamped to the casing 1' by a ring 11 secured to said casing by means of bolts 12 which extend through holes or openings formed in said ring 11 and in the diaphragm 10 and are threaded into holes formed in the flange 5 on said casing 1. In order to bring the ring 11 and the clamping screws 12 entirely above the lower face of the diaphragm 10, a circular groove 13 is formed in the under side of the flange 5 substantially concentric with the casing 1, said diaphragm 10 being formed with a corresponding groove 1d on its under side to receive said clamping ring 11 and with a rib on its upper side adapted to enter the groove 13 in the flange 5 of said casing, the depth of said groove 13 being greater than the aggregate thickness of said diaphragm and ring.

Formed at the center of said diaphragm 10 is a hole or opening 15 surrounding which, at the rear side of said diaphragm, is a flange 16 which extends through the opening? in the spider 6 and outwardly beyond the edges of said hole or opening.

Preferably, also, the diaphragm 10 is pro vided with holes or openings 18 which register with theopenings 8 in the spider 6 for the purpose of better and more thoroughly exhausting the air from between'the diaphragm 10 and the surface of the glass or other article, during'the operation of the machine. Preferably, also, said diaphragm is provided in its under surface with shallowreccsses 19 communicatingwith holes, 13

therein, thereby correspondingly extending the action of the vacuum cup through said holes or. openings 18. V

Adjacent to its outer edge, the diaphragm 1O curves downwardly away from the underface or surface of the vacuum cup 1%. thus imparting to said'diaphragm a shallow cup-' shape so that when said diaphragm is brought into contact'with the surface of an article, as a plate of glass, indicated at 20, Fig. 2, its extreme outer edge'will come into contact with said articleiirst.

The air is then exhausted from the vacuum cup 11, the suction produced thereby, op-

erating on the relatively'thin and flexible outer edges of said diaphragm drawingthe same firmly into contact with the surface of the plate of glass and causing the same to conform exactly to the surface of the glass, including the usual shallow depressions therein, entirely around the circumference of said diaphragm. This contact will operate to prevent any air from entering between said diaphragm and the surface of the glass 20 so that, as the exhaustion of the air inthe vacuum cup A continues the exhaustion of the air from between said diaphragm and the plate of glass 20 will proceed proas at the higher 'partsthereof,thus effectu ally preventing the formation of pockets containing atmospheric air and insuring the full eii'iciency of said vacuum cup in operation.

Formed in the upper end of the Vacuum cup A is an opening 21 which is adapted to be connected with a suitable vacuum pump. by means of suitable pipe connections, not shown, whereby a continuous suction will be produced and a sustained vacuum maintained in said vacuum cup.

I claim 1. A suction device comprising a, body portion, a diaphragm of flexible material secured to the face thereof, said diaphragm being of substantially uniform thickness and being curved away from the body portion.

of said suction device adjacent to. its outer edges, whereby in use theexhaustion of air will proceed progressively from the edges of said diaphragm inwardly, substantially as described.

2. A vacuum cup comprisinga casing one end of which is closed and the other open, said casing being provided with an opening adapted for connection with a vacuum pump or the like, and a diaphragm of flexible material secured to the open end of said casing, said diaphragm being of substantially uni form thickness and being curved away from the body portion of said Vacuum cup adjacent to its outer edge, whereby in use the exhaustion of air will proceed progressively from the edges of said diaphragm inwardly, and said diaphragm being constructed and arranged to conform to the surface of the object to be lifted when compressed against the same, substantially as described.

3. A vacuum cup comprising a casing one end of which is closed and the other open, a flange around the open end of said casing, a spider secured in the open end of said casing provided with a central opening and with other openings outside of said central opening, and a diaphragm of flexible material secured to the open end of said casing, said diaphragm being provided with a central opening and with holes outside of said central opening which respectively communicate with the central and outer openings in said spider, said diaphragm being also provided in its exposed face with shallow recesses communicating with said outer holes therein, said diaphragm being of substantially uniform thickness and being curved away from the body portion of said vacuum cup adjacent to its outer edge, whereby in use the exhaustion of air will proceed progressively from the edges of said diaphragm inwardly, and being constructed and arranged to conform to the surface of the object to be lifted when compressed against the same, substantially as described.

4. A diaphragm for a suction device of the type described, made of flexible material and adapted to conform to the surface of an object when compressed against the same, said diaphragm being of substan-' tially uniform thickness and being curved toward its suction side adjacent to its edges, whereby in use the exhaustion of air will proceed progressively from the edges of said. diapJhragm inwardly, substantially as descri ed.

5. A diaphragm for a vacuum cup of the type described, said diaphragm being of substantially uniform thickness and being curved toward its suction side adjacent to its edge, and being provided with holes adapted to communicate with the interior of a vacuum cup casing and with shallow recesses in its under surface which communicate with said holes, substantially as described.

In testimony that I claim the foregoing as my invention, I afflx my signature in the presence of two subscribing witnesses this 2nd day of April, 1915.

CARLTON L. SMITH.

Witnesses:

ALBERT C. BoRDEN, CHARLES E. ESTABROOK.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

